The examples used are confusing. For instance, some cars can switch between 2-wheel and 4-wheel drive. So how are those cars classified? Surely that would break the hierarchy. Furthermore, I'd argue that 2-wheel and 4-wheel drive aren't classes at all, but attributes of cars.
Also, "The addition of the is-a-subclass-of relationships creates a taxonomy" conflicts with "classes are allowed to have any number of parents (multiple inheritance)." Taxonomies are strict hierarchies that do not allow "multiple inheritance." — Preceding unsigned comment added by 126.96.36.199 (talk) 20:35, 13 July 2011 (UTC)
--- http://www.w3.org/TR/2009/REC-owl2-syntax-20091027/ isn't a bad place to list for sources regarding the main class components. I'm not too good at editing wikipedia, but whoever feels up to a rewrite can maybe use that source? — Preceding unsigned comment added by 188.8.131.52 (talk) 22:18, 20 September 2011 (UTC)
--- In the Classes section, it says "Sometimes restrictions along these lines are made in order to avoid certain well-known paradoxes." The paradoxes are not well-known to me or other beginners, so the article should specify what they are. yewtree (talk) 13:13, 10 June 2013 (UTC)